System and methods for self-decontaminating a surface

ABSTRACT

A system for self-decontaminating a surface of an object is disclosed herein. The system includes a light emitting member and photocatalytic material which can be mounted on or within the object to be decontaminated. Activation of the system releases an oxidizing agent effective in deactivating chemically or biologically active agents at or near the surface. The system is robust, non-destructive, can be activated on demand, and does not require regeneration or expose a user to harmful materials such as UV irradiation. Also disclosed are objects containing the system, methods for self-decontaminating objects using the system, and methods for fabricating self-decontaminating surfaces on an object.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 60/881,200 filed on Jan. 19, 2007.

BACKGROUND

1. Field of the Invention

The invention relates in general to decontamination systems, and moreparticularly to self-decontamination systems.

2. Description of the Related Art

Contamination by harmful biological or chemical agents is a commonoccurrence in everyday life, and decontamination is often required torender such contaminated objects safe for further handling. Conventionaldecontamination systems for sterilizing or cleaning objects, typicallymechanical or chemical in nature, can be used to decontaminate a varietyof objects such as brushes, medical instruments, military equipment, andinterior or exterior walls. These systems generally include theapplication of a decontaminating coating to one or more surfaces on theobject, or confinement of the contaminated object in a decontaminatingenclosure.

One popular type of decontaminating coating contains photocatalyticmaterial which, when exposed to UV light, generates oxidizing speciesthat degrade biological or chemical agents. Oxidative coatings can beused in a variety of situations, including high efficiency particulateair (HEPA) filters and wall paint.

Photocatalytic oxidation is based on the production of several highlyreactive, short-lived chemical species, particularly oxygen-basedradicals and ions that are effective in neutralizing or destroyingmicroorganisms and hazardous chemicals such as volatile organiccompounds (VOCs). One such reaction product, ozone, has the ability tooxidize organic material, including the cell wall of a microorganism.Ozone is a reactive form of oxygen that is a strong oxidant havingdocumented ability to kill spores, bacteria, and viruses. In addition,since ozone is released into the ambient atmosphere during oxidation,the atmosphere immediately surrounding the coating may be decontaminatedat the same time as the coated surface.

Photocatalytic materials can oxidize a wide range of substances and theeffectiveness of photocatalytic oxidation systems has been welldocumented. Photocatalytic particles, coatings, and thin films have, forexample, been demonstrated to oxidize (or reduce) a very wide range oforganic and inorganic compounds at ambient temperatures, pressures, andhumidities. Furthermore, a targeted microorganism is usually completelydestroyed during the oxidation process.

Titania exists in a number of crystalline forms, the most important ofwhich are anatase and rutile. The photocatalytic activity of titaniaresults in thin coatings of the material exhibiting self cleaning anddisinfecting properties under exposure to UV radiation. These propertiesmake the material a candidate for antimicrobial coatings whichpotentially may be used to decontaminate many different types ofobjects, including medical devices, food preparation surfaces, airconditioning filters, sanitary ware surfaces (e.g. toilets, sinks),articles of clothing and the like.

Self-cleaning coatings using photocatalytic titanium dioxide (TiO₂) havegained considerable industry attention in recent years. TiO₂ offers twounique properties: (a) strong oxidation power, and (b)super-hydrophilicity. The first property, strong oxidation power, can beused to kill bacteria attached to a wall or to oxidize/remove foulsmells from stains in a toilet and, as a result, TiO₂-coated tile andTiO₂-coated glass are now commercially available. The second property,super-hydrophilicity, can be used to provide anti-fogging andself-cleaning properties to optical structures in that, when a TiO₂coating is applied to an exterior surface, it allows dirt and stains tobe easily washed away with water or by rainfall. TiO₂ microstructuresalso possess a high refractive index (on the order of about 1.95-1.99)and excellent transparency in the visible range. One popular approach isto apply a coating (e.g. over layer, over material) of TiO₂ tocatalytically decompose chemical or biological agents on the surface ofan object upon irradiation with low level or long wavelength UV lightsources, typically sunlight or fluorescent lamps, respectively.

Self-cleaning and/or disinfecting/sterilizing coatings, structures, andsystems developed for decontamination are disclosed in U.S. Pat. Nos.6,827,910; 6,242,862; 6,242,752; 6,135,126; 6,024,929; 6,099,813; and5,650,126 as well as in U.S. Patent Publication Nos. 2006/0261285;2005/0249955; 2005/0212769; 2005/0191505; 2004/0224145; 2004/0053190,and 2003/0071790. However, each one of these references suffers from oneor more of the following disadvantages: the decontamination process isdependent on sunlight as the UV source (i.e. it can not be usedindoors); the decontamination technique requires an enclosed space orstructure such as an external housing, or an additional, permanentstructural feature such as a cover plate which can alter the dimensionsof the surface targeted for decontamination; the approach can be costlyand/or have impractical logistical requirements such as access toUV-generating equipment and power (e.g. transporting large, fragilemercury lamps and their associated power supplies to remote locationssuch as battlefields); human health or safety may be compromised becausethe user is exposed to and/or in direct contact with UV irradiation orother harmful materials during the decontamination process; thephotocatalytic products generated by the coating attack and damage thesurface during the decontamination or bleaching process; the procedurerequires external ingredients or materials that must be placed inphysical contact with the contaminated surface in order to decontaminateit, the system has low efficiency due to its dependence on low level orlong wavelength UV light sources, or the system either requires a largeor rigid UV lamp as a functional component or a housing containing sucha lamp.

Therefore, a need exists for systems and methods forself-decontamination which can be adapted for use, on demand ifnecessary, in a wide variety of applications and locations. Ideally,such systems should be safe, cheap, robust, non-destructive, portable,and flexible, as well as more efficient, smaller and/or more adaptivethan current technologies.

SUMMARY

The present invention is directed to a photochemically-activated systemfor self-decontaminating a surface on an object. The system includes atleast one light emitting member and at least one photocatalytic materialor coating which are mounted on or within the object. The photocatalyticmaterial is mounted adjacent to the surface and is optically connectedto one or more light emitting members. Activation of the system canrelease an oxidizing agent effective in deactivating chemically orbiologically active agents at or near the surface, or portion thereof,to be decontaminated. The system can be small, safe, non-destructive,robust, and activated on demand, and it does not require regeneration orexpose a user to UV irradiation or other potentially harmful materialsduring use.

The invention also provides objects incorporating the system, methodsfor self-decontaminating an object having the system, and methods forfabricating self-decontaminating surfaces on an object.

In one aspect, the present invention can provide a system forself-decontaminating at least one surface of an object, the systemhaving at least one photocatalytic material and at least one lightemitting member. The at least one photocatalytic material and the atleast one light emitting member are mounted on or within the object, theat least one photocatalytic material is optically connected to the atleast one light emitting member, and the at least one photocatalyticmaterial is adjacent to the at least one surface. In one embodiment, theobject is functionally independent of the system. In another embodiment,the at least one photocatalytic material includes titanium dioxide. Inyet another embodiment, the at least one light emitting member providesultraviolet light. In a further embodiment, the at least one lightemitting member provides ultraviolet light having a wavelength in arange of about 180 nm to about 425 nm. In another embodiment, the atleast one light emitting member is a light emitting diode. In yetanother embodiment, the system further includes adhesive material. Inanother embodiment, the system can be activated on demand. In a yetfurther embodiment, the system can be activated by at least one controlswitch. In another embodiment, the at least one control switch iselectrically connected to the at least one light emitting member, andthe at least one light emitting member provides a quantity of light tothe at least one photocatalytic material upon activation of the at leastone control switch. In a further embodiment, the system further includesat least one reflective element which is optically connected to the atleast one photocatalytic material and the at least one light emittingmember.

In a second aspect, the present invention can provide an object havingat least one system for self-decontaminating at least one surface of anobject, the system having at least one photocatalytic material and atleast one light emitting member. The at least one photocatalyticmaterial and the at least one light emitting member are mounted on orwithin the object, the at least one photocatalytic material is opticallyconnected to the at least one light emitting member, and the at leastone photocatalytic material is adjacent to the at least one surface. Inone embodiment, the object can be a brush. In another embodiment, theobject can be a holder for a toilet plunger. In yet another embodiment,the object can be a tape measure.

In a third aspect, the present invention can provide a method forfabricating at least one self-decontaminating surface on an object. Themethod includes depositing at least one photocatalytic material adjacentto the at least one surface and mounting at least one light emittingmember on or within the object, wherein the at least one photocatalyticmaterial is optically connected to the at least one light emittingmember. In one embodiment, the object is functionally independent of thesystem. In another embodiment, the method further includes depositing atleast one adhesive material adjacent to the at least one photocatalyticmaterial. In yet another embodiment, the method further includescombining at least one adhesive material with the at least onephotocatalytic material. In a further embodiment, the method furtherprovides at least one control switch for activating the system. Inanother embodiment, the at least one photocatalytic material isdeposited adjacent to the at least one light emitting member.

In a fourth aspect, the present invention can provide an object havingat least one self-decontaminating surface fabricated by depositing atleast one photocatalytic material adjacent to the at least one surfaceand mounting at least one light emitting member on or within the object,wherein the at least one photocatalytic material is optically connectedto the at least one light emitting member.

In a fifth aspect, the present invention can provide a method forself-decontaminating at least one surface of an object. The methodincludes: providing a self-decontaminating system having at least onephotocatalytic material and at least one light emitting member;activating the least one light emitting member, thereby inducing the atleast one light emitting member to emit light; and irradiating the atleast one photocatalytic material with at least one portion of the lightemitted by the light emitting member, thereby releasing an oxidizingagent adjacent to the at least one surface of the object. In oneembodiment, the light emitting member is a light emitting diode. Inanother embodiment, the light emitted by the light emitting memberincludes ultraviolet light. In yet another embodiment, the at least onephotocatalytic material includes titanium dioxide. In a furtherembodiment, the oxidizing agent includes ozone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded schematic perspective view of aself-decontaminating brush according to one embodiment of the inventionwhere a photocatalytic layer has been deposited above, and in closeproximity to, an internal light source mounted on the brush head of thebrush;

FIG. 2 is a schematic transverse cross section view of aself-decontaminating brush according to one embodiment of the inventionhaving a wave guide which can transmit light emitted from an externallight source to the brush head via a reflective surface mounted in thebrush head;

FIG. 3A is a schematic transverse cross section view of one embodimentof the invention having a light source coated with a contiguous layer ofphotocatalytic material;

FIG. 3B is a schematic transverse cross section view of one embodimentof the invention having a light source coated with a non-contiguous,beaded layer of photocatalytic material;

FIG. 3C is a schematic transverse cross section view of one embodimentof the invention having a light source coated with a non-contiguous,patterned layer of patterned photocatalytic material;

FIG. 4A is a schematic transverse cross section view of one embodimentof the invention showing a light source coated with a contiguous bilayercontaining a layer of adhesive material adjacent to a layer ofphotocatalytic material;

FIG. 4B is a schematic transverse cross section view of one embodimentof the invention showing a light source coated with a contiguous,blended layer of adhesive material and photocatalytic material;

FIG. 5A is a schematic transverse cross section through the embodimentof the invention shown in FIG. 1 having the bristle support in the brushhead coated with a contiguous layer of photocatalytic material;

FIG. 5B is a schematic transverse cross section view through oneembodiment of the invention showing a brush head having bristles thatare impregnated with photocatalytic material;

FIG. 5C is a schematic transverse cross section view through oneembodiment of the invention showing a brush head having bristles onwhich a non-contiguous, beaded layer of photocatalytic material has beendeposited;

FIG. 6A is a schematic perspective view of one embodiment of theinvention showing a self-decontaminating tape measure having aself-sterilizing measuring tape;

FIG. 6B is a schematic transverse cross section view of the embodimentshown in FIG. 6A;

FIG. 6C is a schematic transverse cross section view of the light wire(94) shown in FIG. 6A;

FIG. 7A is a schematic perspective view of one embodiment of theinvention showing a encapsulating case for a self-decontaminating brush,the case having a closed position; and

FIG. 7B is a schematic perspective view of the embodiment shown in FIG.7A having an open position.

DETAILED DESCRIPTION

The present invention is directed to a photochemically-activated systemfor self-decontaminating a surface on an object. The system can releasean oxidizing agent effective in deactivating certain chemically orbiologically active agents at or near the surface. The system includesat least one light emitting member and at least one photocatalyticcoating which can be mounted on or within a surface of an objectrequiring decontamination. The invention also provides objectsincorporating the system, methods for self-decontaminating an objecthaving the system, and methods for fabricating self-decontaminatingsurfaces on an object.

The present invention can provide systems and methods fordecontamination, particularly self-decontamination, that can be safe,cheap, robust, non-destructive, portable, flexible, more efficient,smaller and/or more adaptive than current technologies.

Other features and advantages of the invention will be apparent from thefollowing detailed description when taken together with the drawings,and from the claims. The following description presents preferredembodiments of the invention representing the best mode contemplated forpracticing the invention. This description is not to be taken in alimiting sense but is made merely for the purpose of describing thegeneral principles of the invention whose scope is defined by theappended claims.

Before addressing details of embodiments described below, some terms aredefined or clarified. As used herein, the terms “comprises,”“comprising,” “includes,” “including,” “has,” “having” or any othervariation thereof, are intended to cover a non-exclusive inclusion. Forexample, a process, method, article, or apparatus that comprises a listof members or elements is not necessarily limited to only those membersor elements but may include other members or elements not expresslylisted or inherent to such process, method, article, or apparatus.Further, unless expressly stated to the contrary, “or” refers to aninclusive or and not to an exclusive or. For example, a condition A or Bis satisfied by any one of the following: A is true (or present) and Bis false (or not present), A is false (or not present) and B is true (orpresent), and both A and B are true (or present).

Also, use of the “a” or “an” are employed to describe elements andcomponents of the invention. This is done merely for convenience and togive a general sense of the invention. This description should be readto include one or at least one and the singular also includes the pluralunless it is obvious that it is meant otherwise.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described below. All publications, patent applications,patents, and other references mentioned herein are incorporated byreference in their entirety. In case of conflict, the presentspecification, including definitions, will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting.

The following definitions refer to the particular embodiments describedherein and are not to be taken as limiting; the invention includesequivalents for other undescribed embodiments.

As used herein, the term “adjacent to” when referring to a layer orcoating on a surface, or to atmosphere adjoining a surface, does notnecessarily mean that the layer, coating or atmosphere is immediatelynext to the surface; there may or may not be another contiguous ornon-contiguous layer or material present between the layer, coating oratmosphere and the surface.

As used herein, the term “adjoining atmosphere” when referring to asurface or portion thereof targeted for decontamination is intended tomean the atmosphere immediately surrounding and which lies in relativelyclose proximity to the surface, including without limitation next to orin contact with the surface.

As used herein, the term “biological agent” is intended to mean one ormore biological organisms and/or their byproducts including withoutlimitation viruses, bacteria, and parasites in any form (includingspores) as well as biologically generated toxins.

As used herein, the term “chemical agent” is intended to mean ahazardous chemical species or compound including without limitationchemical warfare agents and hazardous industrial compounds.

As used herein, the term “coating” is intended to mean one thickness,course, or fold laid or lying over or under another layer or support.The coating may be contiguous or non-contiguous, including withoutlimitation coatings which are uniform, patterned or sprinkled, and maycontain more than one type of material; equivalent terms—over layer,over material.

As used herein, the term “control switch” is intended to mean anysuitable means for activating a source of illumination such anultraviolet lamp on demand, including without limitation a toggle switchon an object or connected to an object via remote control.

As used herein, the term “decontaminate” or “decontaminating” whenreferring to an object or surface is intended to mean devitalizing,deactivating or ridding part or all the object or surface ofcontamination after exposure to one or more toxic agents, includingwithout limitation chemical or biological agents and by-productsthereof. An agent or by-product may be devitalized or deactivated in anumber of ways including, without limitation, oxidation, disinfection ordecomposition. Non-limiting examples of decontamination methods includesterilization, sanitization, deodorizing, and the use of disinfectants.

As used herein, the term “depositing” or “deposition” when referring todepositing materials on a surface is intended to mean any viable methodof deposition including without limitation layering, sprinkling,beading, extruding, patterning, spraying, brushing, rolling, pouring,spin coating, dip coating, ink jet printing, sol-gel processing orapplication of a preform.

As used herein, the term “device” is intended to mean a piece ofequipment or a mechanism designed to serve a special purpose or performa special function.

As used herein, the term “deactivate” or “deactivating” when used todescribe a biological or chemical agent is intended to mean that theagent is destroyed, rendered totally inactive, or made substantiallyless effective.

As used herein, the term “film” is intended to mean a thin covering,material, or coating.

As used herein, the phrase “functionally independent” when referring toan object is intended to mean that the object can perform one or more ofits typical functions in either the presence or absence of aself-decontaminating system or method according to the invention.

As used herein, the term “lamp” when used to describe a light emittingmember is intended to mean any of various devices for producing light orone or more light emitting components thereof, including withoutlimitation a light emitting diode, a light wire containing a pluralityof LEDs, and a glass bulb or tube that emits light produced byelectricity such as an incandescent lamp or fluorescent lamp.Representative examples of light emitting members suitable for theinvention include without limitation electroluminescent, electroactive,and photoactive devices.

As used herein, the term “mounted” when referring to mounting aphotocatalytic material or light emitting member on or within an objectis intended to mean the material or member is attached to the object,including without limitation permanent or temporary attachment to anexterior or interior surface or chamber of the object by chemical,physical or mechanical means.

As used herein, the phrase “optically connected” when referring to aphotoactive material and a light source or light emitting member isintended to mean that light can be provided to the photoactive materialfrom the light source. Examples of optical connections include withoutlimitation a direct connection through close proximity of thephotoactive material to a light source and an indirect connection via anoptical wave guide and/or other optical components such as one or morereflective elements.

As used herein, the term “on demand” when referring to activation of adecontamination system is intended to mean that the system can beactivated or deactivated at will, including without limitation continualactivation, activation at or shortly after the time of exposure tocontamination, or deactivation following a period of time afterexposure.

As used herein, the term “surface” when referring to an object isintended to mean any exterior or interior surface of the object exposedto the atmosphere, or portion thereof, and the adjoining atmosphere.

As used herein, the term “transparent” or “translucent” when referringto a material or layer is intended to mean the material or layer, or aportion thereof, is light-transmissive.

Attention is now directed to more specific details of embodiments thatillustrate but not limit the invention.

FIGS. 1-2 are schematic representations of self-decontaminating brushesaccording to the invention. FIG. 1 shows an exploded, perspective viewof a self-decontaminating brush (10) according to one embodiment. FIG. 2depicts a simplified cross-sectional view of a brush (10) according toanother embodiment. Referring to FIGS. 1-2, the brushes in each of thesetwo illustrated embodiments contain a system for self-decontaminatingsurfaces on the brush head of a brush and, in each embodimentillustrated, the system includes a photocatalytic coating (40) locatedadjacent to the brush head (12) and a light emitting member containingone or more light sources (30) such as one or more LEDs.

As shown in the embodiment illustrated in FIG. 1, a light source (30)can be mounted in a recessed cavity (13) within the brush head (12) of abrush (10), such as a toothbrush, a toilet brush, a hair brush orsubstantially any other brush. The light source (30) can be positionedunderneath the support plate (50) holding the bristles (51) on the brushhead (12), and a photocatalytic coating (40) containing TiO₂ can bedeposited directly on top of the support plate (50). In this embodiment,the photocatalytic coating (40) and light source (30) are placed inrelatively close proximity to each other within the device in order toensure that they are optically connected. Also, in order to maintainthat optical connection in this embodiment, the support plate (50)should be substantially or completely transparent.

Therefore, upon activating the self-decontaminating system shown in FIG.1, the light source (30) in the brush (10) can illuminate thephotocatalytic layer (40) on the support plate (50) containing thebristles (51), thereby generating ozone in and around the photocatalyticmaterial. The ozone generated can decontaminate nearby structures on thebrush head (12), including the support plate (50) and bristles (51)thereon, and the adjoining atmosphere. The brush (10) illustrated inFIG. 1, therefore, can self-decontaminate surfaces on its own brush head(12). The system in this embodiment can be activated by any suitablemeans capable of turning on the light source, including withoutlimitation a turning on the light source, including without limitation acontrol switch (20) on the handle (11) of the brush (10), and anysuitable power supply can be used including without limitation a battery(70) located in the handle (11), as illustrated in FIG. 1.

Many variations of the brush illustrated in FIG. 1 are within the scopeof the present invention. In one embodiment, the photocatalytic coatingcan be deposited inside the light source such as, for example, on thebackside (underside) of the top of the light source, which is typicallya layer of transparent material such as glass, plastic or epoxy. Inanother embodiment, photocatalytic material may be incorporated into oneor more active materials or layers of a UV light source, includingwithout limitation an organic light emitting diode (OLED), such that thelight source itself can generate ozone. In a further embodiment, thephotocatalytic material (40) may be coated on or embedded in thebristles (51) on the brush head (12).

The function(s) of the object can be independent of, and unaffected by,the self-decontaminating system, as illustrated by the embodimentsdiscussed above. However, the light emitting member and/or thephotocatalytic material may be a functional component of the object, aswell as the self-decontaminating system, in other embodiments.

FIG. 2 illustrates another embodiment of the invention in which lightfrom a remote, detachable UV light source can be provided to aphotocatalytic layer on the brush head. In this embodiment, a wave guide(60) spanning the length of the brush (10) can transmit UV light from anexternal UV light source (30) to a photocatalytic layer containing TiO₂(40) underlying the brush head (12) via a reflective element (41). TheUV light source (30) in this embodiment may be located in any suitablelocation external to the brush head (12), including without limitationin an external device such as a support (cradle) or charging device(110), as illustrated in FIG. 2. The light emitting UV light source (30)in this embodiment can be temporarily mounted onto the brush (10) byplacing the brush (10) in an external charging device (110), therebyautomatically aligning the wave guide (60) with the light source (30)and activating the self-decontamination system. The light from theilluminated light source (30) can then travel from the end (62) of thebrush handle (11) nearest the charging device (110), via the wave guide(60), to the end (61) of the brush handle (11) farthest from thecharging device (110) and into the brush head cavity (13). The UV lightentering the brush head cavity (13) can then be reflected upwards by areflective element (41) such that it can irradiate the photocatalyticlayer (40) and thereby generate ozone. After a period of time sufficientto decontaminate the brush head, the brush (10) can then simply beremoved from the charging device (110) in order to deactivate thesystem. In another embodiment, the charging device may contain a controlswitch for the system. In yet another embodiment, the light source (30)may be located within the handle (11) of the brush (10). In anotherembodiment, the photocatalytic material (40) may be coated on orembedded in the bristles (51) on the brush head (12).

The reflective element (41) may be a high gloss reflecting surface suchas a mirror and can contain any suitable reflective material, includingwithout limitation Ni. Nonlimiting examples of suitable optical waveguides include an optical fiber and a rectangular waveguide.

Different types of configurations may be used for activating theself-decontaminating system as needed, including both manual andelectrical control mechanisms. The system can therefore be designed toactivate in a manner appropriate for a particular application, includingwithout limitation activation on demand or for continuous use. In oneembodiment, an internal control switch (20) can be located on the handle(11) of a brush, as illustrated in FIG. 1. A control switch may beactivated by connection to any suitable power supply, including withoutlimitation a rechargeable battery. In another embodiment, a controlswitch may be located in a separate device, including without limitationa cradle or charging device. A control switch can be used to activatethe system on demand, including turning the system on and off atappropriate times/intervals in order to minimize or prevent exposure ofsensitive bodies or surfaces such as skin to potentially hazardous UVirradiation and to save energy when decontamination is not needed. Inyet another embodiment, the system may include a timing circuit or othertype of timer. The system may also be designed to be automaticallyactivated (i.e. without a control switch) by any suitable means,including without limitation placing the brush in a cradle or chargingdevice (110), as illustrated in FIG. 2, or by mounting a charging deviceon the object.

Any suitable external or internal power supply, or connection thereto,can be used for the invention including without limitation an electricaloutlet (e.g. AC socket), drive circuitry, or battery capable ofproviding an appropriate voltage to the system either directly orindirectly (e.g. via a charging cradle or other type of external orinternal adaptor). The power supply can be located anywhere on or withinthe object as long as it does not significantly impede the function ofthe object and provides sufficient power to the system toself-decontaminate the object. The battery in the handle of theembodiment shown in FIG. 1, for example, may be located in the head of abrush, along with the photocatalytic material and the light source, inother embodiments.

Many different types of photocatalytic materials may be suitable for theinvention depending upon the application of interest, including withoutlimitation titanium dioxide (TiO₂). For optimal performance, therelative index of refraction of the photocatalytic material should matchthat of the light emitting member.

Light sources other than sunlight and mercury lamps show promise for usein decontamination systems. UV light emitting diodes (LEDs), forexample, can offer many benefits over sunlight and mercury lamps assources of UV irradiation. LEDs can be “instant-on”, potentially muchcheaper, easily portable, and have a higher theoretical efficiency. Theycan also be smaller and more robust than mercury lamps, and multipleLEDs may be readily bundled into flexible structures such as lightwires. UV LEDs have also been demonstrated to sterilize water spikedwith bacteria and to disinfect small objects placed within structures(e.g. housings) containing such lamps. Many types of UV light sourcesmay be suitable for use in the invention, including inorganic andorganic LEDs.

The light emitting member should emit light in a wavelength rangeappropriate for photoactivating the photocatalytic material. A systemcontaining TiO₂ as the catalytic material, for example, may contain a UVlight emitting member, including without limitation one that emits UVlight with a wavelength in the range of about 180 nm to about 425 nm. Avariety of types of light emitting members can be suitable for theinvention, depending on the nature of the surface to be decontaminated,including without limitation one or more independent light sources suchas UV LEDs, a light wire containing one or more light sources such as UVLEDs, a light guide that can transmit light such as UV light from aremote light source, or a laser such as a UV laser (e.g. if a UV lightsource is located in a housing or other type of enclosure).

A variety of techniques can be used to mount the light emitting memberat, within, or near the surface of interest, including withoutlimitation soldering, ultrasonic bonding, double sided tape orconductive adhesive. One nonlimiting example of conductive adhesive isconductive epoxy.

The photocatalytic material/coating in the system can be prepared byblending the photocatalytic material (typically as a fine powder) and asuitable solvent to form slurry, and then depositing the slurry adjacentto the surface of an object. Solvents suitable for use with theinvention include without limitation organic solvents and water-basedsolvents for polymeric materials such as paints. FIGS. 3A-3C illustratethree exemplary methods of depositing photocatalytic material adjacentto a surface. In one embodiment, photocatalytic material (40) can bedeposited as a single and contiguous layer on the surface of a lightsource (30), as shown in FIG. 3A. In another embodiment, photocatalyticmaterial (40) can be deposited on a light source (30) as a plurality ofnon-contiguous beads, as shown in FIG. 3B. In yet another embodiment,photocatalytic material (40) may be deposited as a non-contiguouspatterned layer during deposition on a light source (30), as shown inFIG. 3C.

The optimal thickness of the photocatalytic coating will be dependentupon the photocatalytic materials used, the type and positioning of thelight emitting member, and the nature of the surface to bedecontaminated. The coating can be solidified and/or attached to thesurface by any suitable means, including without limitation having thematerial cast, pressed into a pellet, or cured by air, heat, or UVirradiation.

The system may also contain adhesive material which binds thephotocatalytic coating to a surface, as shown in FIGS. 4A-4B. In oneembodiment of the invention, the adhesive material (35) can be depositedas a layer on the surface of a light source (30) and the photocatalyticmaterial deposited as a contiguous layer (40) adjacent to the adhesivelayer, as shown in FIG. 4A. In another embodiment, the adhesive materialmay be blended with the photocatalytic material prior to deposition, andthen deposited (e.g. extruded) as a single composite layer (50) on asurface such as a light source (30), as shown in FIG. 4B. Adhesivematerials suitable for the invention include without limitation epoxy,plastic, and adhesive film or tape. The optimal thickness of theadhesive material will be dependent upon the adhesive and/orphotocatalytic materials used, the type and positioning of the lightemitting member, and the nature of the surface to be decontaminated. Foroptimal performance, the relative index of refraction of the adhesivematerial (35) or composite adhesive-photocatalytic material (50) shouldmatch or substantially match that of the light source (30). The adhesivematerial can be cured, if necessary, by any standard means forsolidifying the composition which does not affect the activity of theadhesive or photocatalytic material, including without limitation theuse of inherent properties of the adhesive material or externalmanipulations such as air drying, heat, pressure, UV irradiation, andcombinations thereof. In one embodiment, for example, the adhesive maybe cured by activating a light emitting member in theself-decontaminating system.

Photocatalytic and adhesive materials suitable for use with theinvention may be transparent or translucent with respect to thewavelength of the light source (e.g. transmissive to UV light if thelight source is a UV light source), and sufficiently porous (i.e.breathable) to let in the water, oxygen, or other reagents required forphotocatalysis. Several suitable oxidizing agents can be provided by thesystem, depending upon the nature of the photocatalytic materialpresent, including without limitation those containing one or moreoxidizing species such as ozone. In addition, the self-decontaminatingsystem should generate a sufficient concentration of oxidizing agent tosterilize the surface adjacent to the photocatalytic material/coating.In practice, for systems generating only ozone as the oxidizing agent,at least about 1 μmoles of ozone may be required for the system ofoperate effectively. Furthermore, since the gaseous ozone diffuses awayfrom the surface with time, certain embodiments of aself-decontaminating system may be more effective when placed in anenclosure such as a cutlery drawer or tight-fitting housing (e.g. pen,door knob, brush, or measuring tape).

The photocatalytic layer may be applied to any suitable surface on theobject where it can be optically connected to an appropriate lightsource. FIGS. 1, 2 and 5A illustrate non-limiting embodiments in whichthe bristle support (50) in the brush head (12) of a brush (10) may becoated with a contiguous layer of photocatalytic material (40). Inanother embodiment, the bristles (51) of the brush head can beimpregnated with photocatalytic material (40), as illustrated in FIG.5B. In yet another embodiment, a non-contiguous layer of photocatalyticmaterial (40) may be deposited on the bristles (51) of the brush head,as illustrated in FIG. 5C where beads of photocatalytic material (40)are deposited on the surface of one or more bristles (51).

FIGS. 6A-6C are schematic representations of one embodiment of aself-decontaminating tape measure according to the invention, a tapemeasure having a retractable, self-sterilizing measuring tape. In thisembodiment, the tape measure (90) can include a housing (91) with arotatable spool (92) mounted therein. A length of illuminable tape (93)can be wound upon the spool (92). A light wire (94) containing a stringof LEDs coated with a photocatalytic material (95) can be mounted on thetop side of the measuring tape (93). The coated LEDS (95) in the lightwire (94) can be electrically connected to each other or and/or to apower supply in any suitable manner, including without limitation byelectrical wires or wiring (96). In another embodiment, the light wire(94) may be attached to the tape measure (90) via transparent orsubstantially transparent epoxy. In yet another embodiment, the lightwire (94) may be mounted on the underside of the measuring tape.

The illuminable tape (93) can also include a linear measuring scale (97)printed thereon. The illuminable tape (93) may be pulled from thehousing to expose the linear measuring scale (97) and the light wire(94). The housing (91) may include a partially, substantially, orcompletely transparent portion (98) allowing light emitted from theilluminable tape (93) to illuminate and/or escape the housing (91) insome embodiments. In other embodiments, the housing (91) can be opaqueand the system may be activated when the tape (93) is retracted into thehousing. The tape aperture (98) can be dimensioned to allow theilluminable tape (93) to pass through the aperture (98) as the userpulls the illuminable tape (93) from the housing (91). The housing (91)may also include a power supply for illuminating the LEDs (95),including without limitation a battery (70) which may be electricallyconnected to the LEDs (95). Alternatively, the LEDs (95) can beilluminated by providing an electrical connection to an external powersupply, including without limitation a connection to a power supply viaa charging cradle or other type of adaptor connected to an electricaloutlet/drive circuitry and capable of providing an appropriate voltageto the system.

One non-limiting example of a light wire (94) structure suitable for theinvention is illustrated in FIG. 6C. This embodiment includes multipleLED light sources having a photocatalytic coating (95), as illustratedin FIG. 3A. The LEDs are electrically connected by wires (96) andsurrounded by an external casing (100). The embodiment illustrated mayinclude a polymer ribbon (casing) having one or more apertures that caneach receive an LED (95). In one embodiment, the wires (96) can bewirebonded along the ribbon and, when they reach an LED (95), can bewirebonded to the LED (95). In another embodiment, the LEDs (95) mayhave a portion missing, such that both electrodes on the LED (95) can beaccessed from one side. Several exemplary light wire configurationssuitable for the invention are disclosed in U.S. patent application Ser.No. 11/453/470. The light wire may be attached to the tape using anysuitable means including clear epoxy, which can provide physicalintegrity to the LED as well as a suitably matched index of refraction,or a conformal coating such as a composition containing pre-formed filmand glue. Alternatively, the configuration of the LEDs (95) in the lightwire (94) can be rotated by 180 degrees (flipped) such that thephotocatalytic layer (40) is sandwiched between the LED light source(30) and the tape (93).

The efficiency of the system and methods of the invention can beoptimized by modifying the object as long as the modification does notsubstantially affect the function of the object. The cavity (13) of thebrush head (12) shown in FIG. 1, for example, can be formed in aparabolic shape in order to direct more light upwards towards thephotocatalytic material (40) on the brush support (50).

The systems and methods of the invention are highly adaptable and thusshould serve a wide range of applications. Objects such as door knobs,walls, combs, hairbrushes, nail brushes, toilet plungers, tape measuresand medical instruments are only a few potential applications theself-decontaminating systems of the present invention may be suitablefor. Embodiments using one or more LEDs as a light source, for example,can be highly adaptable. LEDs come in a variety of sizes and shapes, thephotocatalytic coatings can be deposited in a range of shapes and sizes,and light wires containing multiple LEDs having photocatalytic material,whether inside, outside, or not physically connected to the LEDs, canalso be extremely flexible.

Suitable exposure periods for self-decontamination can vary dependingupon the object and application. In some embodiments, an exposure timeof about 15 minutes to about 30 minutes should be sufficient to for theobject to self-decontaminate. The ability to activate the system ondemand also ensures that self-decontamination can take place when theobject is not in use, such as after a person has finished brushing theirteeth, and thus should pose no threat to the safety, health orwell-being of the user.

Due to the relative rates of buildup versus diffusion of the activeagent produced by the catalytic layer, including without limitationgaseous ozone, the systems and methods of the present invention may beparticularly efficient in closed systems. Photocatalytic materials andLEDS can, for example, be strategically placed inside a drawer or withina container in which an object can rest during the decontaminationprocess and, in some embodiments, also for storage purposes. A holder orcover for a toilet brush or toilet plunger, for example, may containsurfaces having photocatalytic material and LEDs, including light wiresof sufficient length and flexibility to cover the space needed todecontaminate a brush or plunger after use.

FIGS. 7A-B show a closed and open variant, respectively, of one type ofencapsulating case (enclosure) suitable for use with aself-decontaminating brush according to the invention such as thoseillustrated in FIGS. 1-2. In the closed position shown in FIG. 7A, thebrush head section (112) of the case (110) can envelope, and thereforecontain the atmosphere around, the brush head (12) of the brush (10).The handle section (111) of the case (110) can similarly envelope thehandle (11), or suitable portion thereof, of the brush (10). The brush(10) can be removed after decontamination (e.g. for storage and/or use)by opening the case (110) as shown in FIG. 7B. In order to facilitatefacile and repetitious opening and closing of the case (110) in thisembodiment, the brush head section (112) of the case (110) can befabricated as an upper (112 a) and a lower (112 b) portion which can beflexibly connected by a living hinge (113). The handle section (111)adjacent to the brush head section (112) can be similarly fabricated asan upper (111 a) and a lower (11 b) portion. The case (110) can be heldtogether during use by any suitable mechanical or physical means,including without limitation an interlocking tongue (114 a) in groove(114 b) connection as illustrated in FIG. 7B. In other embodiments, theshape of the encapsulating case can vary according to the shape of theobject or surface to be decontaminated and the photocatalytic materialand light emitting member used for decontamination. Any suitablematerial can be used to fabricate such a case, including withoutlimitation polypropylene.

The embodiments and examples set forth herein were presented to explainthe nature of the present invention and its practical application, andthereby to enable those of ordinary skill in the art to make and use theinvention. However, those of ordinary skill in the art will recognizethat the foregoing description and examples have been presented for thepurposes of illustration and example only. The description as set forthis not intended to be exhaustive or to limit the invention to theprecise form disclosed. Many modifications and variations are possiblein light of the teachings above without departing from the spirit andscope of the forthcoming claims. One skilled in the art will recognize,for example, that the dimensions, structure, composition, orconfiguration of the system components disclosed, and the types ofobjects rendered self-decontaminating by such systems, may vary andaccordingly are not to be construed as limiting the scope of theinvention.

1. A system for self-decontaminating at least one surface of an object,the system comprising: at least one support plate; at least onephotocatalytic material; at least one light emitting member capable ofgenerating ozone; and a reflective element mounted on, or within, theobject and positioned between the at least one light emitting member andthe at least one photocatalytic material and is optically connected tothe at least one photocatalytic material and the at least one lightemitting member, the reflective element being further positioned withina light path of the at least one light emitting member, wherein thereflective element has a length that is approximately equal to the atleast one support plate and is configured to direct light emitted by theat least one light emitting member directly at the at least one surfaceof the object; wherein the at least one photocatalytic material and theat least one light emitting member are mounted on, or within, theobject, wherein the at least one photocatalytic material is opticallyconnected to the at least one light emitting member, and wherein the atleast one photocatalytic material is adjacent to the at least onesurface and is disposed on the at least one support plate forfacilitating self-decontamination of the object.
 2. The system of claim1, wherein the object is functionally independent of the system.
 3. Thesystem of claim 1, wherein the at least one photocatalytic materialcomprises titanium dioxide and is capable of generating oxidizingspecies.
 4. The system of claim 1, wherein the at least one lightemitting member provides ultraviolet light.
 5. The system of claim 4,wherein the at least one light emitting member provides ultravioletlight having a wavelength in a range of about 180 nm to about 425 nm. 6.The system of claim 1, wherein the at least one light emitting membercomprises at least one light emitting diode.
 7. The system of claim 1,further comprising at least one adhesive material.
 8. The system ofclaim 1, wherein the system is activated on demand.
 9. The system ofclaim 8, wherein the system is activated by at least one control switch.10. The system of claim 9, wherein the at least one control switch iselectrically connected to the at least one light emitting member, andwherein the at least one light emitting member provides a quantity oflight to the at least one photocatalytic material upon activation of theat least one control switch.
 11. An object comprising at least onesystem according to claim
 1. 12. The object of claim 11, wherein theobject is at least one of a brush, a toilet plunger holder, and a tapemeasure.
 13. The system of claim 1, the reflective element comprises areflective surface having a length that is approximately equal to alength of the at least one support plate.
 14. The system of claim 13,wherein the at least one reflective surface is positioned at an anglerelative to the at least one support plate.
 15. The system of claim 1,wherein the object comprises bristles extending from a surface of theobject, where the length of the reflective element is approximatelyequal to a length of an area of the surface from which the bristlesextend.
 16. A system for self-decontaminating at least one surface of anobject, the system comprising: at least one support plate; at least onephotocatalytic material; at least one light emitting member capable ofgenerating ozone; at least one adhesive material; and at least onereflective element mounted on, or within, the object and positionedbetween the at least one light emitting member and the at least onephotocatalytic material, wherein the at least one reflective element isoptically connected to the at least one photocatalytic material and theat least one light emitting member, the at least one reflective elementbeing further positioned within a light path of the at least one lightemitting member, where the at least one reflective element is configuredto direct light emitted by the at least one light emitting memberdirectly at the at least one surface of the object, and where the atleast one reflective element has a length approximately equal to alength of the at least one support plate; wherein the at least onephotocatalytic material and the at least one light emitting member aremounted on, or within, the object, wherein the at least onephotocatalytic material is optically connected to the at least one lightemitting member, wherein the at least one photocatalytic material isadjacent to the at least one surface and is disposed on the at least onesupport plate for facilitating self-decontamination of the object,wherein the object is functionally independent of the system, whereinthe at least one photocatalytic material comprises titanium dioxide andis capable of generating oxidizing species, wherein the at least onelight emitting member provides ultraviolet light, wherein the at leastone light emitting member provides ultraviolet light having a wavelengthin a range of about 180 nm to about 425 nm, wherein the at least onelight emitting member comprises at least one light emitting diode,wherein the system is activable in a manner selected from a groupconsisting essentially of being activable on demand and being activableby at least one control switch, wherein the at least one control switchis electrically connected to the at least one light emitting member, andwherein the at least one light emitting member provides a quantity oflight to the at least one photocatalytic material upon activation of theat least one control switch.
 17. The system of claim 16, wherein the atleast one reflective element comprises a reflective surface that ispositioned at an angle relative to the at least one support plate.